INTEGRATED LOGISTICAL SUPPORT OF AERONAUTICAL EQUIPMENT BASED ON PROBABILITY-GUARANTEEING ESTIMATION OF THE RISKS, ASSOCIATED WITH THE AIRCRAFT TECHNICAL CONDITION

2021 ◽  
pp. 29-37
Author(s):  
V. N. Evdokimenkov ◽  
R. V. Kim ◽  
M. N. Krasilshchikov ◽  
N. I. Selvesyuk
Keyword(s):  
Residual Life ◽  
A Priori ◽  
Estimation Method ◽  
Integral Characteristic ◽  
Technical Condition ◽  
Physical Parameters ◽  
Additional Element ◽  
Flight Data ◽  
Integrated Logistical Support ◽  
Information Database

In this article, we analyze the modern concepts in the field of the aeronautical equipment integrated logistical support (ILS). The key element of the traditional logistical support system under consideration is the data on detected failures and malfunctions, recorded in the air flight and maintenance log (AFML), chart-orders, non-routine write-ups and accumulated within the structure of the logistic support analysis database. We propose a method for expanding the ILS capabilities by means of including of an additional element, called the flight information database, in the logistics center structure, along with the traditional database for analyzing the logistical support. This database is constantly growing during the aircraft operation. It also contains the values of the parameters recorded by the standard onboard flight data recorder, which reflect the state of the onboard systems. The inclusion of a flight information database into the structure of the logistical support center makes it possible to implement the probability-guaranteeing estimation method in respect of the risks, associated with the aircraft technical condition, for benefit of the integrated logistical support. The proposed method uses an inverse probabilistic criterion (quantile) as an integral characteristic of the aircraft systems technical condition. This is fully consistent with modern approaches to organizing condition-based maintenance. Among these approaches, the data-driven methodology (DDM) has the greatest potential and practical efficiency. The applicative value of the described method is in the fact that its implementation needs neither a priori information about the principles of the maintained equipment operation, nor information about the functioning principles of the on-board controller network, which is used to control the equipment physical parameters. In this article, we also present the accuracy estimates of forecasting the residual life of an aircraft gas turbine engine, using the proposed method. These estimates are based on the actual flight data presented in the National Aeronautics and Space Administration (NASA) repository.

Examination of State of the Cable Insulation by the Return Voltage

2018 ◽  
Vol 19 (6) ◽  
Author(s):  
Dmitry Semenov ◽  
Anna Sidorova ◽  
Pavel Romanov ◽  
Aleksey Kuvshinov
Keyword(s):  
Residual Life ◽  
Technical Condition ◽  
Actual State ◽  
Power Cables ◽  
Insulation Resistance ◽  
Cable Lines ◽  
P Factor ◽  
Paper Insulation ◽  
New System

Abstract The relevance of the study is conditioned by the need to determine the state and residual life duration of high-voltage cable lines to identify faulty and maintainable cables. The aim of the article is to determine a reliable scientifically grounded criterion for assessment of insulation characteristics of the cables in use and to perform a comparative analysis of the results obtained by the traditional method of diagnosing insulation with the results of a new method of assessment by the return voltage. In this regard, the article deals with the issues related to the testing of cables having oil-impregnated paper insulation, as well as with the issue of switching from planned replacement of cables to assessment of their actual state and period of residual life. The authors propose to use the method of examining the cables by the return voltage using the device for testing electrical insulation “UDEI-1” developed at the department of Electrification and Automation of the Nizhny Novgorod State University of Engineering and Economics. The article presents the results of measuring the return voltage of three cables that operated under different conditions. The cables had different technical state. The analysis of the estimation of the residual life of cables by the return voltage was carried out using such criteria as the PIRV polarization index, the LIRV electrical conductivity index, and the P-factor. The P-factor is the physical criterion demonstrating the aging of paper-oil insulation by the shape of the return voltage curve. It represents such characteristics of insulation aging as moistening. To compare the results of testing the cables by the return voltage with the conventional methods of diagnostics and to determine the actual technical condition of power cables, the authors applied the method of spatiotemporal reflectometry and the method of measuring insulation resistance with the determination of such indicators of state as insulation resistance normalized per one kilometer, absorption coefficient, and polarization index. The results of this article confirm that the return voltage gives a qualitative assessment of the state and degree of aging of cables with impregnated paper insulation. The authors proposed a new system for evaluation of cable condition by weighting coefficients. In this approach, the determination of residual life of cables with impregnated paper insulation is based on the values of the return voltage. Application of the new system gives opportunity to improve reliability of the power lines. Recommendations for the further operation of the studied cables are given. The materials of the article are of practical value for carrying out complex assessment of the technical condition of power cables by the return voltage and can be useful for drawing up a schedule for replacement or repair of cable lines depending on their actual state.

scholarly journals MODEL DECOMPOSITION BASED ABNORMAL PARAMETER ESTIMATION FOR DISTILLATION COLUMN

2018 ◽  
Vol 48 (2) ◽  
pp. 81-87
Author(s):  
W. D. TIAN ◽  
S. L. SUN
Keyword(s):  
Parameter Estimation ◽  
Nonlinear Model ◽  
Distillation Column ◽  
Estimation Method ◽  
Matrix Analysis ◽  
Physical Parameters ◽  
Time Saving ◽  
Model Decomposition ◽  
Parameter Estimation Method ◽  
Occurrence Matrix

Parameter estimation method can produce useful physical parameters in finding abnormal causes, but nonlinear model makes this method computationally intensive and non-robust for distillation scenario. In this paper, we propose a model decomposition based parameter estimation method for distillation column diagnosis purposes. Nonlinear first principles dynamic model is divided into some disjoint submodels through occurrence matrix analysis. The whole model is used to monitor distillation process and the submodel that gives the highest contribution to the generated residual is selected to perform abnormal parameter estimation. Application results from stripping tower in the popular Tennessee Eastman challenge problem show that the model decomposition based diagnosis scheme is more time-saving and robust than pure nonlinear model based scheme.

scholarly journals The Parameter Estimation of Double Exponential Pulse Based on a Least Infinity Norm Fitting Method

2021 ◽  
Vol 2083 (4) ◽  
pp. 042002
Author(s):  
Yuewu Shi ◽  
Wei Wang ◽  
Zhizhen Zhu ◽  
Xin Nie
Keyword(s):  
Estimation Error ◽  
Estimation Method ◽  
Maximum Amplitude ◽  
Least Square Method ◽  
Least Square ◽  
Physical Parameters ◽  
Infinity Norm ◽  
Fitting Method ◽  
Double Exponential ◽  
Exponential Pulse

Abstract This paper presents an estimation method of double exponential pulse (DEP) between the physical parameters rise time (t r), full width at half maximum amplitude (t FWHM) and the mathematical parameters α, β. A newly fitting method based on the least infinity norm criterion is proposed to deal with the estimation problem of DEP. The calculation process and equation of parameters of this method is proposed based on an m-th-order polynomial fitting model. This estimation method is compared with the least square method by the same data and fitting function. The results show that the maximum estimation error of parameters of double exponential pulse obtained by the least infinity norm method is 1.5 %.

scholarly journals ОСОБЛИВОСТІ АВТОМАТИЗАЦІЇ КОНТРОЛЮ ТЕХНІЧНОГО СТАНУ МОРСЬКОГО ТРАНСПОРТУ

World Science ◽  
2019 ◽  
Vol 1 (3(43)) ◽  
pp. 19-25
Author(s):  
Коломієць Оксана Михайлівна
Keyword(s):  
Water Transport ◽  
A Priori ◽  
Technical Condition ◽  
Software Implementation ◽  
Effective Strategy ◽  
Kutta Method ◽  
A Priori Information ◽  
Automated Control ◽  
Runge Kutta Method ◽  
Priori Information

The article analyzes the principles of automation of the control of the technical condition of water transport vehicles, which has been determined: the principle of coherence; the principle of integration; Principle of independence of execution.It is determined that the most effective strategy is to improve the methods of automated control of the technical condition of water transport vehicles, which, unlike existing ones, is based on Markov processes, the Runge-Kutta method of numerical solution of the system of Kolmogorov differential equations and a priori information about the intensity of transitions from state to state.Using the software implementation of the model significantly improves performance due to the ergonomics of the interface and reduced number of operations.

Effect of Load-Dependent Friction on the Estimation of Rack Force in Electric Power-Assisted Steering System

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Yijun Li ◽  
Taehyun Shim ◽  
Dexin Wang ◽  
Timothy Offerle
Keyword(s):  
Electric Power ◽  
A Priori ◽  
Estimation Method ◽  
Estimation Algorithm ◽  
Steering System ◽  
Estimation Methods ◽  
Current Steering ◽  
Force Estimation ◽  
Operation Conditions ◽  
Friction Estimation

The rack force is valuable information for a vehicle dynamics control system, as it relates closely to the road conditions and steering feel. Since there is no direct measurement of rack force in current steering systems, various rack force estimation methods have been proposed to obtain the rack force information. In order to get an accurate rack force estimate, it is important to have knowledge of the steering system friction. However, it is hard to have an accurate value of friction, as it is subject to variation due to operation conditions and material wear. Especially for the widely used column-assisted electric power steering (C-EPAS) system, the load-dependent characteristic of its worm gear friction has a significant effect on rack force estimation. In this paper, a rack force estimation method using a Kalman filter and a load-dependent friction estimation algorithm is introduced, and the effect of C-EPAS friction on rack force estimator performance is investigated. Unlike other rack force estimation methods, which assume that friction is known a priori, the proposed system uses a load-dependent friction estimation algorithm to determine accurate friction information in the steering system, and then a rack force is estimated using the relationship between steering torque and angle. The effectiveness of this proposed method is verified by carsim/simulink cosimulation.

scholarly journals A practical information-centered technique to remove a priori information from lidar optimal-estimation-method retrievals

2019 ◽  
Vol 12 (7) ◽  
pp. 3943-3961 ◽  
Author(s):  
Ali Jalali ◽  
Shannon Hicks-Jalali ◽  
Robert J. Sica ◽  
Alexander Haefele ◽  
Thomas von Clarmann
Keyword(s):  
Water Vapor ◽  
A Priori ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Mixing Ratio ◽  
A Priori Information ◽  
Fine Grid ◽  
Large Power ◽  
Priori Information ◽  
Water Vapor Mixing Ratio

Abstract. Lidar retrievals of atmospheric temperature and water vapor mixing ratio profiles using the optimal estimation method (OEM) typically use a retrieval grid with a number of points larger than the number of pieces of independent information obtainable from the measurements. Consequently, retrieved geophysical quantities contain some information from their respective a priori values or profiles, which can affect the results in the higher altitudes of the temperature and water vapor profiles due to decreasing signal-to-noise ratios. The extent of this influence can be estimated using the retrieval's averaging kernels. The removal of formal a priori information from the retrieved profiles in the regions of prevailing a priori effects is desirable, particularly when these greatest heights are of interest for scientific studies. We demonstrate here that removal of a priori information from OEM retrievals is possible by repeating the retrieval on a coarser grid where the retrieval is stable even without the use of formal prior information. The averaging kernels of the fine-grid OEM retrieval are used to optimize the coarse retrieval grid. We demonstrate the adequacy of this method for the case of a large power-aperture Rayleigh scatter lidar nighttime temperature retrieval and for a Raman scatter lidar water vapor mixing ratio retrieval during both day and night.

scholarly journals Retrieval of temperature and water vapor profiles from radio occultation refractivity and bending angle measurements using an Optimal Estimation approach: a simulation study

2005 ◽  
Vol 5 (6) ◽  
pp. 1665-1677 ◽  
Author(s):  
A. von Engeln ◽  
G. Nedoluha
Keyword(s):  
Water Vapor ◽  
Radio Occultation ◽  
A Priori ◽  
Estimation Method ◽  
Lower Troposphere ◽  
Optimal Estimation ◽  
Pronounced Difference ◽  
Bending Angle ◽  
Advantages And Disadvantages ◽  
The Impact

Abstract. The Optimal Estimation Method is used to retrieve temperature and water vapor profiles from simulated radio occultation measurements in order to assess how different retrieval schemes may affect the assimilation of this data. High resolution ECMWF global fields are used by a state-of-the-art radio occultation simulator to provide quasi-realistic bending angle and refractivity profiles. Both types of profiles are used in the retrieval process to assess their advantages and disadvantages. The impact of the GPS measurement is expressed as an improvement over the a priori knowledge (taken from a 24h old analysis). Large improvements are found for temperature in the upper troposphere and lower stratosphere. Only very small improvements are found in the lower troposphere, where water vapor is present. Water vapor improvements are only significant between about 1 km to 7 km. No pronounced difference is found between retrievals based upon bending angles or refractivity. Results are compared to idealized retrievals, where the atmosphere is spherically symmetric and instrument noise is not included. Comparing idealized to quasi-realistic calculations shows that the main impact of a ray tracing algorithm can be expected for low latitude water vapor, where the horizontal variability is high. We also address the effect of altitude correlations in the temperature and water vapor. Overall, we find that water vapor and temperature retrievals using bending angle profiles are more CPU intensive than refractivity profiles, but that they do not provide significantly better results.

Meta-analysis, military expenditures and growth

2019 ◽  
Vol 56 (3) ◽  
pp. 352-363 ◽  
Author(s):  
Filiz Yesilyurt ◽  
M Ensar Yesilyurt
Keyword(s):  
Meta Analysis ◽  
A Priori ◽  
Estimation Method ◽  
Core Sample ◽  
Military Expenditure ◽  
Negative Results ◽  
Three Samples ◽  
Study Characteristics ◽  
Military Expenditures ◽  
The Military

This article conducts a meta-analysis of the effect of military expenditures on growth within a structured analytic framework. We extend the pioneering study of Aynur Alptekin and Paul Levine, by using a much larger sample of studies. Like them we confine our attention to studies that use the share of military expenditure in GDP, the military burden, as the independent variable, but unlike them we include not just those that use the military burden directly, what we call the core sample, but also those that use other functions of it, such as logarithms, differences, etc., which we call the remaining sample. We also consider an overall sample which pools all results. The t-statistic on the coefficient of military burden is used as the dependent variable. Our null hypothesis is that military expenditure has no significant effect on growth and we explain why this is plausible. The estimates are sensitive to the sample and type of data used, estimation method adopted, and the controls included. Overall, the results are consistent with the hypothesis of no effect: the average effect across all studies is close to zero. Certain study characteristics appear significant determinants of the effect of military expenditure on growth, but there does not appear to be a simple pattern and different characteristics were significant in the three samples. This might be a result of data mining to produce a significant result. However, there does not appear to be strong evidence of publication bias towards positive or negative results, perhaps because there is no strong a priori belief in the direction of the effect.

On-site investigation and forecast of changes in characteristics of ground water intake in time

2020 ◽  
pp. 66-71
Author(s):  
V. V. Ivashechkin ◽  
◽  
V. I. Kritskaya ◽  
V. N. Anufriev ◽  
A. N. Kondratovich ◽  
...  
Keyword(s):  
Water Intake ◽  
Dynamic Equilibrium ◽  
Residual Life ◽  
Pressure Head ◽  
Site Investigation ◽  
Technical Condition ◽  
Maintenance And Repair ◽  
Water Pipes ◽  
Pump Testing ◽  
Pump Pressure

The on-site investigation of groundwater intakes is carried out to obtain and update the actual parameters of the equipment and structures of a water intake, to optimize its operation modes with an analysis of their changes in time in order to plan maintenance and repair. This article discusses an improved methodology for examining individual elements and structures of groundwater intakes, which allows us to evaluate their current technical condition and to make a predictive calculation of changes in well productivity for the next period of operation based on the solution of the equations of dynamic equilibrium. The technique of clogging assessment allows determining ageing coefficients and approximate residual life of wells; the estimate of the rated pump pressure head reduction due to wear enables the pump testing during its operation at the well and timely replacement of the pump for routine repair; assessment of pipe sculling makes it possible to account for hydraulic resistance of lines connecting the wells to prefabricated water pipes during operation.

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